Topics 2016

Classically, there have been two major groups of underwater vehicles, AUVs and ROVs. Evolving technology allows us to blur the lines between remote and autonomous underwater vehicles in support of increasingly complex and multipurpose missions. Durval Tavares, CEO and CTO of Aquabotix Technology Corporation, discusses the design of the Hybrid ARV (autonomous remote vehicle). Tavares addresses the software and hardware upgrades that make both wide-area autonomous reconnaissance and more targeted remotely controlled monitoring possible using one vehicle.

“Lessons learned from the preparation of off-the-shelf electronic components for the pressure-tolerant usage in deep-sea” – by Peter Kampmann (DFKI GmbH)

This talk gives an overview on the experiences made at the DFKI RIC during transforming standard components like webcams and lightings from off-the-shelf components to deep-sea capable components operating at depths of up to 6,000m. It will give insights on testing and tools used and derive some best practice approaches.

The use of underwater robots has become pervasive and mainstream, fueled by improvements in capability and reliability as well as an ever more attractive price-performance ratio. One of the key elements of an underwater robot is the propulsor, most often a thruster. Aside from the obvious system performance requirements, there are numerous other factors that must be considered in the design of an effective and trouble-free thruster. This paper catalogs and introduces the key considerations for these design requirements.

Remotely Operated Vehicles (ROVs) are becoming more and more widespread throughout the subsea industry. Customers often request that custom hardware (sonar systems, contact probes, grippers/cutters, additional cameras, etc) be integrated into their systems. A customer’s need for a customized ROV is directly at odds with a manufacturer’s desire to produce standardized systems, as the latter lend themselves to mass production and thus benefit from reduced per-system costs and increased reliability. This is particularly true for inspection class ROVs, which are large enough to carry a variety of instruments, and can interact with the environment using a variety of actuators/sensors such as grippers, probes, brushes, etc. The smaller observation class ROVs have a more narrowly defined role (remote camera on a mobile platform) which greatly simplifies the optimization task for mass production. Larger working class vehicles, being much greater capital investments (and requiring substantially more infrastructure to deploy), are relatively poor candidates for mass production because their sales generally do not support it.

An inspection class ROV in the subsea industry has a natural analog in the automotive sector: the pickup truck. Like inspection class ROVs, pickup trucks need to get the jobsite, often must carry out a variety of physical tasks, be able to carry a wide range of payloads, put up with a substantial amount of wear and tear, and – perhaps most importantly – are almost infinitely customizable using 3rd party accessories. Despite the broad range of demands placed on pickup trucks by their owners & potential customers, they have been adapted to mass production because their designers have embraced the “well-defined vagueness” of their roles and have tailored their design/manufacture to it. They also are amongst the most profitable vehicles in the automotive industry.

In this talk, I will provide an overview of Seamor Marine’s Chinook & Steelhead inspection class ROV systems, and describe how the above analogy has guided their design & development. Key to this development has been well-defined interfaces – not just within the ROV itself, but within the tether and surface control systems – allowing improvements to various subsystems independent of each other. A clear line between the ROV and the payloads that it might be required to carry (including many that we have yet to even consider) facilitates the mass production of the core system and gives rise to a set of electrical & mechanical interfaces enabling the straightforward integration of a wide variety of payloads, sensors, and accessories that also can be removed easily and cleanly. A direct benefit of this approach is component reuse, which has further improved system reliability and lowered costs due to the streamlined manufacturing & testing process. The result is a highly reliable ROV that literally can grow in its capabilities with the needs of the customer.

Coral Reef health measurements are invaluable to understanding the effects of enviromental changes on the world’s oceans. Several projects are currently underway to develop a better understanding of reef status. Many of these projects involve satellite imagery and hyperspectral analysis; some projects involve divers filming the coral and processing those images into three-dimensional maps. The goal of our project is to provide high resolution three-dimensional data maps developed using a low cost remotely operated vehicle (ROV). We will use our ROV to map the same area year after year and provide annual maps and delta maps for marine research. The ROV that we have developed was designed to be constructed with commercial off-the shelf components and supports a development trajectory that goes from remote operation to semi-autonomous operation to fully-autonomous operation. Research and development has cost us approximately §25,000 and has yielded a vehicle with five degrees of freedom capable of depthsup to 150 ft and generates up to 42 ft-lb of thrust in the horizontal motion plane and 30 ft-lb of thrust in the vertical motion plane. Our architecture is such that simple replacement of existing components would result in a vehicle with more depth capability and power without having to redesign the system. Using the same parts usppplier, we can achieve depths of 450 ft by substituting parts at an dditional cost of $3000.

The Graphical USer Interface (GUI) was designed to support Situation Awareness (SA) using SA design principles. The interface consists of three pages with depth, speed, horizontal orientation, heading and primary camera feed available on all three pages. The orimary page adds the reverse facing camera while the other two pages include vehicle operational characteristics and sensor data respectively. To further support affordability, the primary physical user interface is a standard Sony Playstation style controller.

The software is being developed using the Robotics Operating System (ROS) on machines running the Ubuntu Linux operating system. This approach allows us to create a scalable robust software architecture that easily supports future expansion.

We are nearing completion of construction and will begin field testing, including map generation, the end of the year. Testing and validation of the ROV and GUI will consist of pool testing of the vehicle followed by deployment testing in a freshwater lake enviroment. During lake testing, we will be developing a simulator to allow for testing and evaluation of the GUI. Successful completion of testing will allow us to move forward with a real world mapping mission. Several sites are being evaluated and a final selection is expected early in the Spring of 2016.

Underwater gliders are a family of Autonomous Underwater Vehicles (AUV) that utilizes the modulation of buoyancy and center of gravity in order to manipulate their pitch and depth. During these vertical excursions wings are used for propulsion and directional control. This low impact, low energy propulsion makes seagliders well suited for oceanography, and extended environmental research. In these extended deployments the seaglider is expected to autonomously collect data about the surrounding water column, including temperature, salinity, and current, and every few oscillations surface and transmit the collected data. The saw tooth profile the seagliders fly allows them to cover many thousands of miles and remain in the field for many months at a time. However, the vertical excursions often occur at high angles of attack. This in turn limits the usefulness of the seaglider in terms of both endurance and as a sensing platform. This research proposes addressing this problem by using an annular wing, a configuration that is being investigated for multiple uses in the aerospace industry. By utilizing an annular wing, the seaglider will improve performance at higher angles of attack, including station keeping maneuvers. This paper discusses the method of implementation of an annular wing on an autonomous seaglider as well as its impact in terms overall performance. To achieve this a simulation was developed in which various parameters, including center of gravity, center of buoyancy, and angle of incidence can be varied and their impact on performance tabulated. These results will then be compared to experimental results.